Sims hugging backwards/arm glitches

My sims stretch randomly and weirdly sometimes, mostly when I think they trying to hug each other or interact with pets. I've seen a sim sit in a chair doing a really weird stretching glitch while another sim was hugging the air in the room next door for example. Another time a sim went all stretched and distorted and I think he was trying to pet the cat in the garden outside. Another time a sim looked like he might be trying to harvest fruits (from a tree in the garden, which is outside and he was in the house). It's not always clear what interaction goes wrong, though.